The thermal efficiency and hence the output power of an engine of a saddle-ridden vehicle such as a motorcycle can be increased by equipping the engine with a supercharger and supplying air that has been compressed by the supercharger to the combustion chambers of the engine. JP-A-2015-83437 discloses a saddle-ridden vehicle which is equipped with a supercharger.
The saddle-ridden vehicle disclosed in JP-A-2015-83437 is equipped with an air cleaner for cleaning external air, a supercharger for compressing air cleaned by the air cleaner, an intercooler for cooling air that has been compressed by the supercharger and thereby made high in temperature, and a surge tank for supplying air cooled by the intercooler after storing it temporarily. In this saddle-ridden vehicle, an air intake pipe connects the air cleaner and the supercharger. An air outlet pipe connects the supercharger and the intercooler. The intercooler and the surge tank are adjacent to each other and a short pipe connects them directly.
On the other hand, an electronically controlled throttling method is known in which an accelerator manipulation amount of a rider is detected by a sensor and an electric drive motor is operated on the basis of the detected accelerator manipulation amount, whereby the degree of opening of a throttle valve is controlled. JP-A-2002-256895 discloses a throttle control device that employs the electronically controlled throttling method.